From: AdaMagica <christ-usch.grein@t-online.de>
Subject: Re: What is the history behind Natural'First = 0 ?
Date: Fri, 1 May 2020 01:38:12 -0700 (PDT)
Date: 2020-05-01T01:38:12-07:00 [thread overview]
Message-ID: <0632fbec-c29f-40c8-8b78-9ee2aaef7723@googlegroups.com> (raw)
In-Reply-To: <r8gkf4$ul2$1@dont-email.me>
Am Freitag, 1. Mai 2020 09:52:05 UTC+2 schrieb J-P. Rosen:
> Le 01/05/2020 à 06:51, reinert a écrit :
> > Why Natural'First = 0 ?
> >
> Because that's the way it is ;-)
>
> Anyway, type Integer is not the mathematical notion of (infinite)
> integers, and more generaly computer types are only reduced abstractions
> of mathematical notions.
Being a wiseacre, I'd like to point out out RM 3.5.4(8):
The set of values for a signed integer type is the (infinite) set of mathematical integers[, though only values of the base range of the type are fully supported for run-time operations].
> There is a need for a subtype of type Integer with lower bound 0, and
> another one for lower bound 1. The names have been chosen by Ichbiah
> following usual practice, they could have been anything else.
Yes, could have been Natural and Natural_0. I find Ichbiah's choice optimal.
next prev parent reply other threads:[~2020-05-01 8:38 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-01 4:51 What is the history behind Natural'First = 0 ? reinert
2020-05-01 7:52 ` J-P. Rosen
2020-05-01 8:38 ` AdaMagica [this message]
2020-05-01 10:24 ` J-P. Rosen
2020-05-01 19:03 ` Keith Thompson
2020-05-01 21:36 ` Robert A Duff
2020-05-03 20:08 ` Keith Thompson
2020-05-04 3:02 ` Keith Thompson
2020-05-04 8:50 ` Paul Rubin
2020-05-04 14:22 ` Dennis Lee Bieber
2020-05-01 10:13 ` Jeffrey R. Carter
2020-05-01 18:14 ` Optikos
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